Rotary printing drum for duplicating machines



R. w. BAILEY 2,743,670

ROTARY PRINTING DRUM FOR DUPLICATING MACHINES May 1, 1956 INVENT'O. R. WBAILEY 4 Sheets-Sheet 1 BY 62w Original Filed July 21, 1949 QTTOQWEY.

ROTARY PRINTING DRUM FOR DUPLICATING MACHINES Original Filed July 21,1949 R. W. BAILEY May 1, 1956 4 Sheets-Sheet 2 INVENTOR. R. WBAILEYflrroewsx y 1956 R. w. BAILEY 2,743,670

ROTARY PRINTING DRUM FOR DUPLICATING MACHINES Original Filed July 21,1949 4 Sheets-Sheet 5 as 6 62 as 82a INVENTOR. R .WBAILEY y L 1956 R. w.BAILEY 2,743,670

ROTARY PRINTING DRUM FOR DUPLICATING MACHINES Original Filed July 21,1949 4 heets-Sheet 4 137: L (J57 125 133 I INVENTOR.

a 154 7 RW BAILEY ROTARY PRINTING DRUM FOR DUPLICATING MACHINES RichardW. Bailey, Pasadena, Calif., assignor to Milo Harding Company, LosAngeles, Calif., a partnership composed of Milo M. Harding and James M.Harding Original application July 21, 1949, Serial No. 105,942, nowPatent No. 2,697,397, dated December 21, 1954. lzgigiggg and thisapplication July 16, 1951, Serial No.

13 Claims. (Cl. 101 119) This invention relates to duplicating machines,mimeographs and the like; more particuarly, it relates to the rotatabledrum commonly provided in such machines for mounting the stencil.

It is an object of this invention to provide an improved drum of thistype.

Such drums commonly comprise a perforated cylindrical shell about whichthe stencil is wrapped, a thin layer of porous material such as muslinbeing interposed. Ink within the drum and in contact with the shellfeeds outwardly through the stencil as the drum is rotated, printing aform in accordance with the cutting of the stencil on paper urgedagainst the stencil by passing between the drum and an impressionroller.

This application is a division of an application, Serial No. 105,942,filed July 21, 1949, for Rotary Drum for Duplicating Machines, nowPatent No. 2,697,397.

The perforated cylindrical portion of the shell on which the stencil ismounted is usually substantially less than the entire circumference ofthe drum and somewhat less than the length of a stencil. The remainderof the circumference being offset inwardly to accommodate the stencilmounting means etc., exteriorly thereof. As the drum rotates, the ink onthe inner surface of the shell tends to lag behind the movement of theshell, and furthermore is urged outwardly by centrifugal force. Thereduced portion of the shell retards the movement of the ink, so thatthe ink accumulates adjacent the trailing end of the cylindrical shell,the corresponding end of the stencil thus having too much ink while thehead or leading end of the stencil has too little.

It is accordingly another object of this invention to provide aduplicator drum so arranged as to prevent such accumulation of ink.

it is another object of this invention to provide a duplicator drumhaving means to facilitate transfer of ink between the opposite ends ofthe cylindrical portion of the shell.

Conventional stencils for duplicating machines are usually made of suchsize as to accommodate matter filling a legal size sheet; on the otherhand, a large proportion of the matter to be printed is readilyaccommodated on a letter size sheet. Thus, there is frequently a spaceat the lower or trailing end of the stencil which is not used. Asdiscussed hereinbefore, the ink tends to accumulate in the drum shellover this part of the stencil, and frequently builds up sufficiently toescape along the opposite edges of the stencil, or to cause the stencilto wrinkle, as well as other difiiculties, particularly when this partof the stencil is not cut. It is accordingly another object of thisinvention to provide a duplicator drum or the like arranged to preventleakage of ink and/or injury to the lower or trailing end of the stencilwhen printing a letter size form.

It is another object of this invention to provide a duplicator drum orthe like, having optionally operable means for diverting the ink fromthat portion of the drum shell covered by the trailing end of thestencil.

2,743,670 Patented May 1, 1956 It is another object of this invention toprovide a duplicator drum or the like, having optionally operable meansfor masking that portion of the drum shell covered by the trailing endof the stencil to prevent escape of ink through the shell perforations.

This invention possesses many other advantages and has other objectswhich may be made more easily apparent from a consideration of severalembodiments of the invention. For this purpose there are shown severalforms in the drawings accompanying and forming part of the presentspecification. These forms will now be described in detail, illustratingthe general principles of the invention; but it is to be understood thatthis detailed description is not to be taken in a limiting sense, sincethe scope of the invention is best defined. by the appended claims.

In the accompanying drawings:

Fig. l is a longitudinal sectional view of a duplicating.

machine, showing in elevation a drum incorporating features of theinvention;

Fig. 2 is a transverse section on an enlarged scale and partly inelevation, taken substantially as indicated by line 22 of Fig. 1;

Fig. 2-a is a detail section, taken substantially as indicated by line2a-2-a of Fig. 2;

Fig. 3 is a top plan view, seen as looking down in Fig. 2;

Fig. 4 is a sectional view, similar to Fig. 2, but on a further enlargedscale and showing a diiferent operating position of the parts;

Fig. 5 is a cross section, taken substantially as indicated by line 5-5of Fig. 4;

Fig. 6 is a fragmentary section on an enlarged scale,

taken substantially as indicated by line 6-6 of Fig. 5;

Fig. 7 is a fragmentary cross section on an enlarged scale, takensubstantially as indicated by line 7-7 of Fig. 3;

Fig. 8 is a fragmentary section on an enlarged scale, takensubstantially as indicated by line 8-8 on Fig. 3;

Fig. 9 is a fragment of a section similar to Fig. 5, but showing amodified form of the invention;

Fig. 10 is a view similar to Fig. 9 but showing a different operatingposition of the parts;

Fig. 11 is a sectional view, similar to Fig. 4, but showing anothermodified form of the invention;

Fig. 12 is a cross section taken substantially as indicah ed by line12-12 of Fig. 11; and

Figs. .13 and 14 are fragmentary sections taken substantially asindicated by the correspondingly numbered lines of Fig. 12.

Referring to Fig. 1, a duplicating machine embodying the presentinvention is shown schematically and comprises a frame generallyindicated by the numeral 1, having upstanding side members 2 and 3 (seealso Figs. 2 and 3) which cooperate to support the printing drum 5 forrotation about a horizontal axis 6, the drum being driven in acounterclockwise direction by suitable means (not shown). As shown inFig. 2, the drum 5 has a shell 7 covered in part by an ink pad 8 and astencil sheet 9, a layer of ink (not shown) being provided on the innersurface of the shell 7 for passage through perforations therein to thestencil. Sheets of paper Ill or other suitable material are fed from thestock pile 11 between the drum 5 and the inn pression roller 12 to beprinted in accordance with the cutting of the stencil, the printedsheets 10' being delivered to the magazine 13.

Referring to Figs. 2 to 8, the drum 5 comprises a pair of circular heads20 and 21 joined in spaced relation by the shell 7. As best shown inFig. 5, the shell has a cylindrical perforated portion 22 which isdiscontinuous, that is, it extends less than a full circumference, theopposite ends thereof being connected by a solid portion 23 spaced ra-The plate 25 has a pair of apertures 26, each of which is engaged by amember 27 slidable on the solid shell portion 23 and urged in adirection to tighten the pad 8 by adjustable spring means 29. Theopposite ends 8b may be pro vided with a similar plate which catchesbehind a short extension 22-a of the cylindrical shell portion 22, or asshown in Fig. at 34 the end of the pad 3 may be merely folded over thisextension 22-a, since there is very little forceacting on the pad.

The stencil 9 is entirely conventional and comprises a paper stiffeneror reenforcing strip 31 at its head or leading end with a plurality ofkey-hole shaped apertures 32 therein, engageable respectively byprojections or fingers 33 formed on a bar 34 extending across the drum 5and supported for angular movement about its axis by reduced portions34-a and 34-1) engaging suitable openings in the heads and 21respectively.

The arrangement is such that the bar 34 is oscillatable between aposition in which the fingers or projections 33 are inclined away fromthe stencil as shown in Fig. 5, and prevent its removal, and a positionsubstantially 90 therefrom permitting ready attachment or removal of astencil. A light tension spring 35 (Figs. 3 and 8) urges the bar 34 tostencil retaining position, a short lever 36 being provided tofacilitate operation of the bar 34 to stencil releasing position. Forthis purpose, the arcuate cover plate 37 must first be moved to permitaccess to the bar 34, lever 36, etc., as will be discussed hereinafter.The lever 36 also serves by means of a lug 36-a engageable with theshell portion 23 to appropriately limit movement of the bar 34 by spring35.

The opposite or trailing end of the stencil 9 is also secured to thedrum 5. Thus, as shown in Fig. 5, the length of the stencil sheet 9 issuch that the sheet extends beyond the extension 22-a and along theshell portion 23. An elongated member 40 extending across the drum 5 hasa forward edge 40-a adapted to engage the stencil 9 immediately adjacentthe extension 22-11 for this purpose being rotatably mounted on the bar41 by the aid of webs 40-b. A pair of tension springs 42 anchored at 43on the shell portion 23 (see Fig. 7) and connected to a flange 40-0 onthe member 40 urge the member 40 about the bar 41 so that the edge 40apresses against the stencil 9. For

moving the member 40 into and out of engagement with the stencil, bar 41is pivotally mounted inthe heads 20 and 21 by offset pintles 44 and 45,one of which, as 45, extends through the head 21 and has an operatingknob 47 secured thereon.

As clearly shown in Figs. 5 and 7, the pintles 44 and are so locatedwith respect to the points of attachment of the springs 42 as to form anover center arrangement wherein the member 40 in either stencil engagingposition or releasing position is urged about the bar 41 by the springs42 m'a clockwise direction. Thus, in stencil engag ing position, theforward edge 40-a of the member 40 clamps the trailing end of thestencil 9 against the shell portion 23, and in stencil releasingposition engages the shell portion 23 at a point spaced from saidstencil end, thereby releasably maintaining the member 40 againstmovement.

The foregoing manner of mounting the stencil 9 enables the removal ofthe head end of the stencil first, animportant advantage since. this endhas the reenforcing piece 25 and is free of ink. However, if desired,the stencil 9 may. be removed in conventional manner by operating theclamping member 40 to release the trailing or rear end first. I

The arcuate plate 37 is provided. to form a protection cover for thehead of the stencil 9 and the anchoring means therefor, being mountedfor movement about the axis of the drum 5 between a closed positioncovering said head and stencil means and an open position in which theyare exposed for manipulation. For this purpose, the opposite edges ofthe plate 37 are slidingly accommodated respectively in grooves 50 and51 in the heads 20 and 21. A latch member 53 (Fig. 7) is pivotallymounted on the inside of the plate 37 by the aid of ears 54, being urgedby a spring 55 so that its inner end 53-a normally engages the shellportion 23. The opposite end of the member 53 has a thumb button 53-bthereon accommodated in an opening 37-11 in the plate 37. The inner end53-a of the member 53 by engaging a stop lug 56 on the shell portion 23,serves to releasably maintain the plate 37 in closed position. Pressureon the thumb button 53-b disengages the member 53 from the lug 56,.sothat the plate 37 may be moved to open position.

The ink for the stencil is supplied to the interior of the drum 5through an opening 60 in the shell portion 23, closed by a threaded plug61. With the advent of thinner quick drying inks, it is important thatthe amount of ink in the shell is not excessive further it isadvantageous to be able to replenish the ink supply in an appropriateamount and without the need of removing the plug 61' concentric with theperforated shell spaced inwardly therefrom and supported by upright endplates 65 and 66 having hubs 65-a and 66a which engage the tubularmember, or axle 63. A tie plate 67 extends between the upper ends of theplates 65 and 66.

The cradle 62 has an elongated opening 68 in the bottom plate 64, aswell as an intermediate plate 69 with a similar opening or aperture 70,providing first and. second or upper and lower ink containing chambers71 and 72. A closure member 73 is suspended between the bottom 64 andthe intermediate plate 69 by a pivoted link 74 connected to one arm of alever member 75 rockably supported between upstanding ears formed on theopposite edges of the bottom plate 64, one of such ears being indicatedat 76, Figs. 2 and 4. As clearly shown in Figs. 4 and 5, the closuremember 73 comprises a metal plate 73-a of such size as to overlie theopenings 68 or 7 0 and connected to link 74 by the aid of lug 73-11. Aresilient pad '78 is provided on the upper face of plate 73-a forsealing about the aperture when the closure 73 is in its upper position.A similar pad 79 is provided on the lower face of the plate 73-a forsealing about the opening 68 when the closure 73 is in its lowerposition, this pad 79 however being somewhat thicker toallow forthecurvature of the bottom plate 64.

The arrangement is such that the closure 73, normally closes the bottomopening 68, the aperture 70 being open, so that the ink chambers 71 and72 are in free communication but no ink can pass onto the interiorsurface of the drum 5. However, the closure 73 is optionally operable touncover the bottom opening 68 and close the aperture Thus, by making theupper chamber 71. To facilitate the emptying and filling of the lowerchamber 72, appropriate air vents 77 are provided at each end thereof.

For operating the lever 75 a sleeve 80 is rotatably and slidably mountedon the axial member 63 and has a notched lug 80-a engaging a notch 75-bin arm 75-a of the lever 75. This prevents rotation of the sleeve 80 aswell as constraining the lever 75 to swing in accordance with the axialmovement of the sleeve 80, a compression spring 81 confined between thesleeve 80 and the end boss 65-11, normally maintaining the parts withclosure 73 closing the bottom opening 68.

For moving the sleeve 80 to cause the closure 73 to move to its otheroperating position, a push rod 82 is slidably mounted in the member 63extending inwardly from one end and having a transverse pin 83 adjacentits inner end projecting through oppositely disposed slots 63-a in themember 63. Rollers 84 are provided on the pin 83 for engaging the sleeve80, since the push rod 82 and pin 83 rotate with the member 63, whilethe sleeve 80 remains stationary. The outer end of the rod 82 has aslightly enlarged head 82-a which is sealed against the bore in member63 as by a conventional 0-ring 85 accommodated in a groove in the head82-11.

The opposite end of the member 63 has an elongated plug 86 securedtherein with a through axial opening 86-41 to be more fully discussedshortly. A compression spring 88 confined between the plug 86 and rod 82urges the rod 82 outwardly, pin 83 by engagement with the ends of slots63-11 serving to limit such movement. Means to be discussed hereinafterare provided for urging the rod 82 inwardly to operate the closure 73.

It will be obvious that the closure 73 must not dwell at an intermediatepoint with both openings 60 and 70 simultaneously uncovered, since thiswould prevent proper metering of the ink delivered to the interior ofthe drum 5. To insure proper operation of the closure 73, it iscontinually biased by the spring 81 to close the lower opening 68, thisforce being supplemented by that of a leaf spring 89 confined betweenarm 7S-c of the lever 75 and the end plate 65. This spring 39 isarranged in a known manner to exert a force opposing movement of thelever 75 from either limiting position and which increases as the leverreaches an intermediate position. Thus, while the force of spring 81overrides the force of spring 89, exertion of a force on the lever 75sufiicient to move it from a position in which the closure 73 closes theopening 63 to and through an intermediate position, will insure furthermovement of the lever 75 in response to spring 89 so that the closure 73closes the aperture 70.

. The drum is mounted in the duplicator by the aid of the conical hubs90 and 91 secured respectively to the drum heads and 21, hub 90 beingsecured by a special screw 92 threaded into the plug 86. The hubs 90 and91 respectively engage members 94 and 95 providing conical cups forreceiving the conical surfaces of the hubs 90 and 91, and rotatablysupported by the upstanding side members 2 and 3 of the frame 1. One ofthese cup members, as 94, may be power driven, the drum 5 being indriving relation therewith by a pin 96 in the head 20 engaging slot 94-ain the cup member 9 The screw 92 has a central aperture leading from theaperture 86-01 in the plug 86 to the space between the hub 90 and cup 94(see Fig. 2), communication between this space and the atmosphere beingprovided by one or more transverse grooves 90-41 in the surface of thehub 90. The aperture 36-11 opens into the interior of the member 63which communicates freely with the interior of drum 5 by ports 63-15. Inthis way, atmospheric pressure within the drum is assured at all times.

The other cup member 95 is rotatably mounted on the inner end of a shorthollow shaft 97, but is restrained against axial movement thereon, andmay be optionally driven by means independent of the means driving themember 94, such as a hand crank (not shown) for rotating the drum 5. Forthis purpose the member in= cludes an integral spur gear 95-a and adriving pin 98 is provided in the head 21 engaging a slot 95-]; in themember 95.

The shaft 97 is supported for angular and axial movement in the frameupright 3 by means of a bushing 100 fixed therein, a knob 101 beingsecured on the outer end of shaft 97 to facilitate its operation.Appropriate movement of the shaft 97 and member 95 thereon to the left(Fig. 2) will disengage the member 95 from the hub 91 and allow the drum5 to be moved to the left to disengage the hub 90 from the other cup 94,freeing the drum 5 for removal from between the uprights 2 and 3.Similarly, movement of the shaft 97 and member 95 to the right willsecure the drum 5 after it is replaced.

The shaft 97 is resiliently urged to drum retaining position by a detentarm 102 pivotally mounted at 102-a on a plate 103 secured Within theupright 3 about the shaft (Figures 2 and 2-:1). The arm 102 inclinesfrom the end 102-0 away from the plate 103 to the free end which isurged inwardly or toward the drum 5 by a compression spring 104, therebeing a recess 102-12 adjacent the free end normally engaged by a pinprojecting from the shaft 97. The spring 104 thus serves to maintain thedrum 5 in operating position by urging the cups 9d and 95 and theirrespective hubs into engagement.

When it is desired to remove the drum, the operator, by means of theknob 101 exerts sufficient turning force in a counterclockwisedirection, referring to Fig. 2-a, on shaft 97, to force the pin 105 outof the recess 102-17, the shaft 97 then being rotated about 90 to alignpin 105 with a slot 1% extending through the plate 103 and axially inbushing 100. The shaft 97 together with the cup member 95 is then movedaxially to the left to disengage the member 95 and hub 91. Inward andclockwise movement of the shaft 97 will cause engagement of pin 105 anddetent notch 102-11, thus locking drum 5 in place.

An operating rod 107 for actuating the ink feeding mechanism is slidablein the bore of the hollow shaft 97, having a head 107-11 projecting fromthe knob 101 and confining a spring 108 against the end of the shaft 97.The spring 108 urges the rod 107 outwardly, a suitable stop member107-12 on the rod 107 limiting such movement by contact with the innerend of the shaft 97. The inner end of rod 107 is adapted to contact pushrod 82 so that suitable pressure exerted on the head 107-a will actuatethe closure 73 in the manner previously discussed.

The rotation of the drum 5 causes the ink on the inner surface of thecylindrical shell portion 22 to accumulate adjacent the trailing end ofthe shell 22 where it joins the inwardly spaced shell portion 23. Thisis objectionable in any case since it results in an excessive ink supplyfor the trailing end of the stencil and especialiy since the lastseveral inches of the stencil are not cut or used in a large proportionof the work. Accordingly, means are provided optionally operable formasking this portion of the shell 22.

Thus, as shown in Figs. 4 and 5, a plate 110 is provided extendingbetween the heads 20 and 21 and in spaced relation over the trailing endof the shell portion 22 and the adjacent end of the inwardly spacedshell portion 23. At the leading end of the plate 110, a control flap111 is provided, secured on a bar 112 extending longitudinally of thedrum 5 and rotatably mounted at its opposite ends in the drum heads 20and 21 respectively. Bar 112 projects through the head 21 having anoperating knob 113 secured on its outer end.

The arrangement is such that the flap 111 may be positioned as indicatedby full lines to prevent entry of ink between the shell 22 and themasking plate 110 or as indicated by the broken lines to permit ink toenter freely. However, it is to be noted that in the latter case thethickness of the ink layer acting on the trailing end of the shell 22and the stencil 9 can never exceed the 7 distance by which the maskingplate is separated from the shell. As shown in Fig. 6, a spring pressedball 114 may be provided in the head 21 engageable with either of a pairof recesses 115 in the knob 113 for retaining the flap 111 in adjustedposition, appropriate indicia 116 (Fig. 1) being provided on the head 21cooperating with a mark on the knob 113 to indicate the position of theflap 112.

A modified form of means for masking the trailing end of the cylindricalshell portion is shown in Figs. 9 and 10. Therein an arcuate plate 119,adapted to closely engage the inner surface of the shell 22, issupported for swinging movement into and out of contact with the shellby a plurality of longitudinally spaced arms such as indicated by 120pivoted respectively to lugs 121 on the in side of the shell portion 23.A longitudinally extending shaft 122 is rotatably supported at itsopposite ends in the heads 20 and 21 respectively, an operating knob 123being provided on one end thereof as before.

One or more springs 124 tensioned between the shaft 122 and lugs 119-aon the plate 119, urge the plate inwardly of the shell 22, such movementbeing opposed by the engagement of a cam surface 119b with projectingcam means 122-a on the shaft 122, as shown in Fig. 9. Upon rotation ofthe shaft 122 to disengage the cam 122aand the cam surface 119-h, theplate 119 swings inwardly against shaft 122 as a stop, allowing freepassage of ink over the trailing end of the shell 22 (Fig. 10). Reverserotation of the shaft 122 reengages the cam 122-a and cam surface 119-band returns the plate 119 to its masking position, an extension 119-c ofthe cam surface 119-b serving as a stop to appropriately limit rotationof the shaft 122 by engaging the cam 122-a.

In Figs. 11 and 12 a modified form of ink cradle is shown in connectionwith a modified form of printing drum, but it is to be understood thatthere is no especial cooperation between these modified forms, as thedrum of Fig. 11 could as well employ the ink cradle of Figs. 2 to 5, andthe drum of Fig. 2 et seq. could equally as well employ the ink cradleof Figs. 11 and 12.

Referring to Figs. 11 and 12, the printing drum shown therein isgenerally quite similar to the previously described drum comprisingcircular heads 13%) and 131 joined by a shell having a discontinuouscylindrical perforated portion 132 with its ends joined by an inwardlyspaced portion 133.

However, to prevent the previously discussed accumulation of inkadjacent the trailing end of the cylindrical shell portion 132, a pairof channels 134 and 135 are provided' in the inwardly spaced shellportion 133 connecting said trailing end with the leading end of thisportion 132. Thus, the width of the shell portion 133 is less than thespace between the heads and 131 so that the opposite edges thereof arespaced from the heads, means 136 and 137 being provided adjacent theheads 130 and 131 respectively forming narrow continuations of thecylindrical shell portion 132 connecting its opposite ends. The means136 and 137 are connected at their outer edges respectively to the heads130 and 131 and at their inner edges by upstanding walls 138 and 139 tothe shell portion 133. It will be apparent that ink accumulationadjacent the trailing end of the cylindrical shell portion 132 will flowlongitudinally along the shell to the channels 134 and and thence viathe channels to the leading end of the shell portion 132. Since thesechannels 134 and 135 form a continuation of the cylindrical shellportion 132, free fiow of the ink results.

The described arrangement has important advantages in providing auniform distribution of ink over the stencil, avoiding excessive inkingof the trailing end of the stencil while assuming an ample supply of inkfor the head end.

The inking pad 8 and the stencil 9 may be secured to the druminsubstantially the same manner as in the first described form of theinvention. However, as shown in Fig. 13, the anchoring means 140 for thetrailing end of the stencil 9, similar to that previously described, isrotatably supported by engagement of the pintles 140-a and 140-]; withthe channel walls 138 and 139 respec tively, pintle 140-b extendingacross the channel 135 and through the head 131, an operating knob 141being fixed on its outer end. Likewise one end of the anchoring bar 142for the head of the stencil 9, similar to that previously described, isrotatably supported by the channel wall 139 as shown in Fig. 14, theother end being similarly supported by the channel wall 138.

An arcuate protective cover 143 is provided as before, slidably mountedin grooves 144 and 145' defined-respectively by the channel bottoms 136and 137 and flanges 146 and 147 on the heads 130 and 131.

The stationary cradle 150 for containing the ink is generally quitesimilar to that of the first described form of the invention andcomprises an arcuate bottom wall 151 with an elongated opening 152 andan intermediate apertured wall 153 with an opening 154, a closure memher155 similar to that of the first described form of the invention beingprovided for controlling the openings. The cradle 150 is rotatablysupported with respect to the drum by end plates 156' and 157 secured tohubs 158 and 159 and braced by a top spacer plate 161. This plate 161has an opening 161-11 for facilitating the pass age of ink from the drumopening 162.

The hub 153 is rotatably mounted on a tube 163 fixed in the head 131iand extending inwardly therefrom to provide an air vent for the interiorof the drum, a protective cover 164 being provided to prevent accidentalentry of ink into the tube 163. The other hub 159 is rotatably supportedon the axially extending push rod 165 which operates the closure 155.

A lever member 166 is rockably mounted on the spacer plate 161. by theaid of a bracket 167 and is connected to the closure by a link 168. Thelever member 166 has a crank-like lateral extension 169 with a slot169-a for accommodating a reduced neck 165-a on the push rod 165. Thepush rod 165 has a packed head 165-b at its outer end slidable in a bore170 provided in the drum head 131, a spring 171 confined between thehead 165-1) and hub 159 urging the push rod 165 outwardly, to cause theclosure 155 to close the bottom opening 152. Appropriate pressureexerted on the push rod 165, as by the operating rod 107 will cause theclosure 155 to uncover the bottom opening 152 and close the aperture154, thus delivering a metered quantity of ink as determined by thevolume defined between the cradle bottom 151 and the plate 153. Uponrelease of the push rod 165, the closure 155 returns to its normalposition closing the bottom opening 152. A flat spring 172 engagesanextension 166-a of the lever 166 for insuring movement thereof to insuremovement of the closure 155 to close to that in the first described formof the invention.

As in the first described form of the invention, it may" be desirable toprovide optionally operable means for masking the trailing end portionof the shell portion 132, for which purpose, an arrangementsubstantially identical with that disclosed in Figs. 9 and 10 is shown.Thus, an arcuate plate 17? adapted to closely engage the inner surfaceof shell 132, and corresponding with plate 119 of Figs. 9 and 10, issupported for angular movement toward and away from shell 132 by a pairof arms 180, and is optionally movable into and out of masking positionby the aid of a rotatable cam shaft 134 all as before.

I claim:

1. A rotatable printing drum for a duplicating machine, having heads anda shell comprising a perforate cylindrical portion adapted to have astencil sheet secured thereon, and a radially inwardly spacedimperforate portion 'ofiset from said perforate portion, said drum beingadapted to have a body of ink distributed in a layer over the innersurface of said shell for passage through said shell and 182 and tensionspring said stencil, rotation of said shell causingsaid ink layer tomove on said surface toward the rear end of the stencil; and meanscomprising a fixed plate inwardly spaced from said shell and extendingover the rear of the perforate portion thereof, and a gate pivotedadjacent the forward edge of said plate, optionally operable to closethe opening between said plate and said shell and divert the ink layerto the inside surface of said plate.

2. A rotatable printing drum for a duplicating machine, having heads anda shell with a perforate cylindrical portion adapted to have a stencilsheet secured thereon, and an imperforate portion, said drum beingadapted to have a body of ink distributed in a layer over the innersurface of said shell for passage through said shell and said stencil,rotation of said shell causing said ink layer to move on said surfacetoward the rear end of the stencil; means comprising a plate adapted tomask the perforations in the rear portion of said shell and mounted formovement in entirety into and out of contact with the inner surface ofsaid shell; means urging said plate out of contact with said shell; andoptionally operable means for moving said plate into contact with saidshell; said plate when moved in entirety out of contact with said shelldefining between the shell and the plate a through passage through whichink may flow.

3. In a rotatable printing drum for a duplicating machine, a pair ofspaced heads connected by a shell, said shell comprising a perforatecylindrical portion adapted to have a stencil sheet secured thereon, anda radially inwardly spaced imperforate portion offset from saidperforate portion, said drum being adapted to have a body of inkdistributed in a layer over the inner surface of said shell for passagethrough said shell and said stencil, rotation of said shell causing saidink layer to move on said surface toward the rear end of the stencil;means comprising a plate adapted to mask the perforations in the rearportion of said shell; means pivotally mounting said plate for bodilymovement within the shell for movement between a position masking saidperforations and a position wherein they are open; means resilientlyurging said plate to one of said positions; and cam means operable fromthe exterior of the drum for optionally moving said plate to the otherposition said plate when in position to open said perforations,cooperating with said cylindrical portion to form a passage throughwhich ink may flow on the interior of said shell past both ends of theplate.

4. In a rotatable printing drum for a duplicating machine: a pair ofspaced heads connected by a shell; said shell having a perforatediscontinuous cylindrical portion and a radially inwardly spaced portionjoining the ends of said cylindrical portion; and channel forming meansproviding a continuation of said cylindrical portion of restricted widthbetween said ends adjacent said heads for facilitating ink movementwithin the drum in response to rotation thereof, said continuationshaving substantially the same radius as said cylindrical portion.

5. In a rotatable printing drum for a duplicating machine: a pair ofspaced heads connected by a shell; said shell having a perforatediscontinuous cylindrical portion and a radially inwardly spaced portionjoining the ends of said cylindrical portion intermediate said heads andhaving its opposite edges spaced therefrom respectively; means forming acontinuation of said cylindrical portion joining said ends adjacent saidheads and connected thereto facilitating ink movement within the drum;said continuations having substantially the same radius as saidcylindrical portion; and upstanding walls joining the edges of saidcontinuations and of said inwardly spaced portion respectively.

6. In a rotatable printing drum for a duplicating machine: a pair ofspaced heads connected by a shell, said shell comprising a perforatediscontinuous cylindrical portion and a radially inwardly spaced portionjoining the ends thereof; means forming channels in said inwardly spacedportionconnecting said ends for facilitating movement within the drum inresponse to rotation thereof; and optionally operable means to controlpassage of ink through said shell, comprising a bodily movable plateextending over a part of said cylindrical portion, means mounting saidplate for bodily movement toward said shell and into contact therewiththroughout its area and away from said cylindrical portion to provide apassageway open at both ends between said plate and said cylindricalportion; and means for moving said plate.

7. A rotatable drum for a duplicating machine, including a perforateshell adapted to have ink distributed over the inner surface thereof, aradially inwardly spaced imperforate shell portion offset from saidperforate shell, a pair of spaced heads connected by said shell, channelforming means constituting a continuation of said imperforate portionadjacent the heads of said shell, having substantially the same radiusas said perforate shell facil itating the passage of ink, saidperforated shell adapted to have stencil sheet secured over the outersurface thereof, means for masking perforations in said shell, and meansoperable at will for rendering said masking means operative, saidmasking means when inoperative, forming with said shell a passage openat both ends through which ink may flow.

8. A rotatable drum for a duplicating machine, including a perforateshell adapted to have ink distributed over the inner surface thereof, aradially inwardly spaced imperforate shell portion offset from saidperforate shell, a pair of spaced heads connected by said shell, channelforming means constituting a continuation of said imperforate portionadjacent the heads of said shell, having substantially the same radiusas said perforate shell facilitating the passage of ink, said perforatedshell adapted to have a stencil sheet secured over the outer surfacethereof, masking means positioned within said shell operable forexcluding flow of ink through perforations covered by the uncut trailingend portion of the stencil, and means for rendering said masking meansoperative and inoperative, said masking means when inoperative formingwith said shell a passage open at both ends to provide for the flow ofink in either direction between the masking means and said shell.

9. In a rotatable drum for a duplicating machine, a pair of spaced headsconnected by a shell, said shell having a perforate portion adapted tohave ink distributed over the inner surface thereof and a stencil sheetmounted over the outer surface thereof, a radially inwardly spacedimperforate portion offset from the perforate portion, and passageforming means within the drum adjacent the heads and forming acontinuation of said imperforate portion having the same radius as saidperforate portion for conducting ink between the ends of said perforateportion independently of flow of ink over said offset portion.

10. A rotatable drum for a duplicating machine, including a shell havinga perforate portion adapted to have ink distributed over the innersurface thereof and a stencil sheet secured over the outer surfacethereof, masking means interiorly of said shell operable for preventingflow of ink through perforations in said perforate portion, and maskingmeans including a plate mounted in inwardly spaced relation to the innersurface of a part of said perforate portion, and a gate movable into andout of position preventing flow of ink between said plate and said partof said perforate portion; and means operable exteriorly of said shellfor so moving said gate.

11. A rotatable drum for a duplicating machine, including a shell havinga perforate section adapted to have ink distributed over the innersurface thereof and a stencil sheet secured over the outer surfacethereof, an imperforate section between the ends of said perforatesection and offset therefrom, masking means interiorly of said shelloperable for preventing flow of ink through perforations in saidperforate section, said masking means including a plate mounted ininwardly spaced relation to the inner surface of a portion of saidperforate section and a portion of said imperforate section, a gatemovable into and out of position preventing flow of ink between saidplate and said portions and means operable exteriorly of said shell forso moving said gate.

12. In a rotatable drum for a duplicating machine, a pair of spacedheads connected by a shell, said shell having a perforate portionadapted to have ink distributed over the inner surface thereof and astencil sheet secured over the outer surface thereof, masking meansinteriorly of said shell operable for preventing flow of ink throughperforations in said perforate portion, including a plate mounted forbodily movement within said shell for movement into and out of aposition preventing flow of ink through perforations in said perforateportion, and means for so moving said plate, said masking means wheninoperative forming with said shell a passage open at both ends toprovide for the flow of ink. therethrough in either direction betweensaid plate and said shell.

13. A rotatable drum for a duplicating machine, a pair of spaced headsconnected by a shell, said shell having a perforate portion adapted tohave ink distributed over the inner surface thereof and a stencil sheetsecured over the outer surface thereof, masking means interior'ly of"said shell operable for preventing flow of ink through perforations insaid perforate portion, including a plate mounted for bodily movementwithin said shell for move-.

ment into and out of a position preventing flow of ink at both ends toprovide for the flow of ink therethrough in either direction betweensaid plate and said shell.

References Cited in the file of this patent UNITED STATES PATENTS1,687,003 Brasseur Oct. 9, 1928 1,856,18l Burkholdt May 3, 1932'2,162,346 Gregory June 13, 1939 2,186,939 Nigra Jan. 16, 1940 FOREIGNPATENTS 594,195 Great Britain Nov. 5, 1947

